/**
 * This file is part of aionjp.
 *
 *  aionjp is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *
 *  aionjp is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 *
 *  You should have received a copy of the GNU General Public License
 *  along with aionjp.  If not, see <http://www.gnu.org/licenses/>.
 */
package aionjp.network.crypt;

import java.io.IOException;

import aionjp.utils.Rnd;

/**
 * @author KenM
 */
public class LoginCrypt
{
	private static final byte[]	STATIC_BLOWFISH_KEY	= { (byte) 0x6b, (byte) 0x60, (byte) 0xcb, (byte) 0x5b,
		(byte) 0x82, (byte) 0xce, (byte) 0x90, (byte) 0xb1, (byte) 0xcc, (byte) 0x2b, (byte) 0x6c, (byte) 0x55,
		(byte) 0x6c, (byte) 0x6c, (byte) 0x6c, (byte) 0x6c };

	private NewCrypt			_staticCrypt		= new NewCrypt(STATIC_BLOWFISH_KEY);
	private NewCrypt			_crypt;
	private boolean				_static				= true;

	public void setKey(byte[] key)
	{
		_crypt = new NewCrypt(key);
	}

	public boolean decrypt(byte[] raw, final int offset, final int size) throws IOException
	{
		_crypt.decrypt(raw, offset, size);
		return NewCrypt.verifyChecksum(raw, offset, size);
	}

	public int encrypt(byte[] raw, final int offset, int size) throws IOException
	{
		// reserve checksum
		size += 4;

		if (_static)
		{
			// reserve for XOR "key"
			size += 4;

			// padding
			size += 8 - size % 8;
			NewCrypt.encXORPass(raw, offset, size, Rnd.nextInt());
			_staticCrypt.crypt(raw, offset, size);

			_static = false;
		}
		else
		{
			// padding
			size += 8 - size % 8;
			NewCrypt.appendChecksum(raw, offset, size);
			_crypt.crypt(raw, offset, size);
		}
		return size;
	}
}
